Wave generation



June 27, 1933. M. osNos WAVE GENERATION 5 Sheets-Sheet 1 Filed Oct. 15, 1929 BE: 2:: m i

INVENTOR MENDE OSNOS ATTORNEY June 27, 1933. M. \OSNOS 9 3 WAVE GENERATION Filed 001;. 15, 1929 3 Sheets-Sheet 2 Flig4 ATTORNEY June 27, 1933'.

' M. OSNOS WAVE GENERATION File d o t. 15, 1929 3 Sheets-Sheet 5 "mm d a/ I warm All"! Xlllli INVENTOR MENDEL 'OSN05.

ATTORNEY Patented June 27, 1933 UNITED STATES 3&15578 PATENT ossics j MENDEL' osnos, or BERLIN, GERMANY, ASSIGNOR 'IO TELEFUNKEN GESELLSGHAFT FUR DRAHTLOSE TELEGRAPHIE M. B. 11., or BERLIN, GERMANY,.A co'nrommrou OF GERMANY WAVE GENERATION Application filed October 15, 1929, Serial No. 399,727, and in Germany October 20, 1928.

For the purpose of obviating fading and its attendant disturbances, it has been suggested in the prior art to send one and the P same message simultaneously on several waves presenting only a slight difference in frequency. 7

The present invention solves the problem of producing the desired number of such slightly different frequencies by a minimum number of generators, and provides ways and means to make these waves as far as feasible of the same amplitude. I

It is known in the prior art to split a given radio frequency v by means of thermionic tubes comprising a filament and a grid by modulating the grid circuits thereof by a modulating current having frequency m into two dissimilar frequencies v+m) and ('vm).

It has further been suggested to obtain a division of a given radio frequency current into two other frequencies in such a way that a primary current of given radio frequency v and constant amplitude is brought to act upon a secondary circuit by means of a variable coupling which is modulated by a modulator current having frequency m in such a manner that the coupling ratio passes through zero at least twice during each period of the modulating current and changes its. sign.

In all of these schemes disclosed in the prior art the aim is to divide a single input frequency supplied to the modulator means into two other frequencies.

For the purpose of simultaneous production of several radio frequency currents differing but slightly from. one another, according to this invention, each one of the two or more waves is divided into a pair of waves in well-known manner by one and the same modulating current, and, if desired, by one and the same modulator.

Several exemplifications of the basic idea of this invention are illustrated in Figures 1 to 6 of the accompanying drawings.

' Fig. 1 showsa circuit arrangement of wellknown kind. In this scheme, the grid circuits of the thermionic tubes a, a, in Wellknown manner are acted upon by the radio frequency currents in the same sense, andby the modulating current 71 in the opposite sense, while the plate currents of thetwo tubes are in differential coupling relation' ship with the useful or load circuit. The

arrangement shown in Fig. l dilfersfrom by the modulating current, i with the fi e quency m. In this manner, the antenna cir-' cuit (or else the input circuit of the next stage, as the case may be) receives pairs of. frequencies ('v m) and (o +m), (o 'm)' and (c -Fm) (e m) and ('v ,+m), etc.

Hence, generating is many input frequencies '0 v 41 etc. by means of lc-m'any tubes, by the aid of a supplementary pair of tubes (1, a, 2k frequencies are obtained, and for this purpose, as will be noted, only 7c+2 tubes are here required. If each ensuing frequency had been produced in a separate tube, then 2k tubes would have been needed. Hence, by using the scheme here disclosed and illustratedin F ig. 1, (/b2) tubes can be saved.

An arrangement which offers still far greater advantages is'illustrated in Fig. 2. In this scheme, even with a single input frequency '0 any desired great number of ensuing frequencies can be obtained by having recourse to regenerative coupling. In Fig. 2 regeneration is insured, for instance, by means of windings d and s. The input frequency 0 is first split by the modulatingcurrent i into two frequencies a m and '0 +m. Hence, also the tickler or back-feed coil 8 will receive these frequencies. Each of these in turn is divided by the action of the modulating current i into two pai'rs'of frequencies arising in the plate circuits, i. e, o -m+m= o o -mm=o 2m, o +m+m=o1+2m, and 'v +mm=o However, the two waves of frequency '0 become neutralized owing to the push-pull action, so that what remains are frequencies t -rm, o .m, o d-2m, and I) 2m/. The last two of these waves are again fed to the regenerative circuit and are split in o +2m m ='u +m, U '+2I77,l7n=U 't-377L, o 2m m=v,--3m,and'v 2m,+m= v m. Hence, these new frequencies are added, i. e., an +3v n and (0 3771,, and these, if desired, can be split again, and so on. V V In this manner an entire band of frequencies is obtainable, and while the amplitudes thereof may be identical, the frequencies of neighboring 'or adjacent waves will differ from one another by only a small number m.

The number of ensuing frequencies prO- ducible by the aid of a single modulating current isdependent upon the constant of the tubes and the circuits whereby regeneration is insured. By changing the said constants,

also the number of ensuing frequencies is valiable...

In order that the band of frequencies thus obtained may not be unduly wide, suitable band-limiting means may be provided. For

instance, tuned and variable crystal systems kk may be connected either in parallel or in seriesrelation to the grids 'for the said pur- The circuit scheme hereinbefore described can be modified by bringing the back-feed circuit (l, s, in coupling relationship with the gridcircuit of the generator furnishing the original frequency '0 rather than with the grids of the tubes a, a.

[An arrangement of this kind is illustrated in Fig. 3. By regenerative coupling between generator 9 and the output circuit of the tubes a,.a, the former is caused to produce also derived frequencies and these are fed by way of the coupling coil 8 to the grid circuit of the generators a, a. r

The-circuit arrangement shown in Fig. 4 differs from the preceding embodiment only in that, instead of a single tube g, two tubes 9, g in a symmetrical push-pull arrangement are provided. The generator 9, g, is simultaneously with tubes a, a, acted upon by the modulating current i In the absence of the latter, generator. g, 9, produces no radio frequency energy at all. But when the modulating current i,,, arises, then the generator g, g, first produces the original frequency 4),, and this frequency, similarly as before coscribed for the other schemes, is fed to the grid circuit of tubes a, a, wherefrom, by successive divisions and back-feeds, a number of split frequencies are produced. Itwill be understood that the invention not confined to the division of a wave as hereinbefore described into two other frequencies, but it is useful also for other arrangements insuring the division of a radio frequency current into two other frequencies.

Fig. 5 illustrates the application of the basic idea of the invention to an arrangement in which a given radio frequency "0 may be split into two other radio frequencies by that a primary current i of given input frequency 0, and of an amplitude being as constant as possible is brought to act upon another circuit by way of a variable modulable coupling, in such a way that the coupling factor during each period of the modulating current 2' passes at least twice through zero and changes its sign. I

In the exemplification shown, thecoupling is efiected by the aid of a coupler branch comprising an inductance L and a condenser C. By convenient control of this coupling branch, its resultant impedance can be varied at rhythm of themodulating current. For instance, thc choke-coil D can be furnished with an iron-core whose auxiliary or biasing direct current magnetization is varied by the modulating current, though a preferable plan is to provide the condenser C with a quiver or vibrator electrode subjectto. the control of the modulating current 2". For the accurate adjustment of the coupling branch it is also recommended to shunt the constant inductance L by a variable condenser C, thoughin such a manner that the ensuing impedance of the branch thus formed remains inductive. At the mean disance between the two electrodes of the diaphragm condenser C, the resultant reactance w of the entire coupler branch is set to zero, while at smaller distances it becomes inductive and at larger distance capacitive.

To maintain the amplitude of the primary currents 71 at as constant a value as feasible, the generator 5/ producing the same is brought only in loose coupling relationship with the describedfrequency splitting means, and in the latter the coupling coil L0 with the condenser C0 are tuned as correctly as feasible to the range of input frequenciesv to be divided. The original radio frequency input frequency produced by the generator (1,41 isthus modulated by, the coupling branch w in such a manner that the'circuit Z there will be set up two frequencies 'v -lm and 1) m. a

tow, according to this invention, these split frequencies are fed not only to the useful circuit or load circuit (antenna circuit or 7 another stage), but they are also fed by way of regenerative means (Z, s, to the grid circuit of the generator 9 whereby they are amplified, and thereupon transferredagain to the loosely coupled splitting means,

In the embodiments hereinbefore described and illustrated in Figs. 2-5, recourse is had to the principle of regeneration. Another embodiment of the invention is based upon the cascade principle, as illustrated, for example, in Fig. 6. In this scheme, the generators af-a a -'a a 'a each of which comprises push-pull-connected tubes as in the preceding arrangements, are united cascade-fashion and are jointly modulated by the current entially connected with reference to the o-riginal or primary frequency, to the grid circuit of the next cascade stage a -a by the agency of coupling coil 8 In a similar manner, the four additional split frequencies are fed by the coupling circuit d (Z 8 to the grid circuit of the next stage a a It will be understood, of course, that the number of stages may be chosen adlibitum.

It is recommendable, as shown in Fig. 6,

to couple all of the stages with the load cirJ cuit. By varying the couplings, or by other means known in-the art, the amplitudes of diflerent stages may be adjusted at will. Since the coupling may be changed the intensity of the different stages may be varied at will.

The same cascade principle may obviously be applied also, in an analogous manner, to the frequency-dividing means illustrated in F i I n conclusion, the following remarks may be made: Feeding the modulator, in an arrangement according to the present invention, simultaneously with two or more modulating currents of different frequencies, each of these currents will result in a corresponding number of split waves. The total number of such split waves may thus be increased. Now, telephony fundamentally speaking is nothing else but the feeding of the modulator with several modulating currents of different frequencies. Whence it follows that the scheme here disclosed may be advantageously used not only for telegraphy, but also for telephonywork.

I claim r 1. In a system for the generation of electrical wave energy of a plurality of frequencies, a pair of pushpull connected electron discharge devices, means for applying to control electrodes of said devices waves of a plurality of frequencies in parallel, and means for applying in series to said control electrodes waves of another frequency, and, means for feeding back energy from the output circuit of said pushpull connected electron discharge devices to the input circuit thereof.

2. In a system for the production of waves of a plurality of frequencies, a pair of pushpull connected electron discharge devices, means for feeding electrical energy of constant amplitude and of difi'erent frequencies to control electrodes of said pushpull connected devices in parallel, means for feeding electrical energy of a difierent frequency to the control electrodes of said devices in series, means for feeding back energy from the out-- put circuit of said pushpull connected electron discharge devices to the input circuit thereof, and frequency band limiting means coupled to said devices for limiting the frequency band appearing in the output circuit of said devices.

3. In a system for the generation of electrical wave energy of a plurality of closely adjacent frequencies, a pair of pushpull connected electron discharge devices, a generator generating energy of constant frequency coupled to the input electrodes of said devices in parallel, another source of energy of another frequency coupled to said input electrodes in series, and, means for coupling the output circuit of said pushpull connected devices to the input circuit of said generator.

4. In a system for the generation of electrical wave energy of a plurality of closely adjacent frequencies, a pair of pushpull connected electron discharge devices, a generator generating energy of constant frequency coupled to the input electrodes of said devices in parallel, another source of energy of another frequency coupled to said input electrodes in series, means for coupling the output circuit of said pushpull connected devices to the input circuit of said generator, and, frequency band limiting means for limiting in the output circuit of said pushpull connected electron discharge devices the frequency band width of energy.

5. In a system for the generation of electrical wave energy of a plurality of closely adjacent frequencies, a pair of push-pull connected electron discharge devices, a source of energy of a desired frequency coupled to the input electrodes of said devices in parallel, another source of energy of another frequency coupled to said input electrodes in series, and means for coupling the output circuit of said push-pull connected devices to the input electrodes of said devices in parallel.

6. In asystem for the generation of electrical wave energy of a plurality of frequencies, a pair of push-pull connected electron discharge devices, means for app-lying to control electrodes of said devices in parallel waves of a plurality of frequencies, said means comprising at least one source of electrical energy and a coupling circuit from the output of said push-pull connected del vices to the control electrodes.

MENDEL OSN OS. 

